Which gearbox for Race / Trackdays?
 

Hi,

a friend of mine from the German mx-5 board with a 99/00 with GT2560R running at ~11-12 psi constantly eats his 5-speed gearboxes. (Always looses 3rd gear)

Look Ma, no teeth...
http://foto.arcor-online.net/palb/al...6362363430.jpg

http://foto.arcor-online.net/palb/al...3465333464.jpg

http://foto.arcor-online.net/palb/al...3533333765.jpg

We have a quite long thread now at the German borad but there are not too many track-driving turbo-equipped cars over here.

He is running a lot of trackdays at The Ring so he really puts a lot of track-use to the gearboxes...

What would you recommend him to do?

- 6-speed
- 5-speed or 6-speed oil-cooled with external oil-cooler
- FM gearbox
- other options

Thanks for the advice (especially from all the Track-gurus...)

6-speed, no question. Every fast Cali track car runs one. My 5-speed lasted 6,000 miles, and my 6-speed has been in its place for 25k+. I rebuilt it a couple months ago due to a botched shift - I moved the seat forward a bit after repainting the car and my normal backhanded 5-6 motion found the reverse gate at ~130mph. I got to inspect the internals while we were going over the damaged parts - everything looked great, even after a year of hard track use. We replaced the reverse gear, slider, synchro, and the 5-R shift fork, and left everything else in place. I do not baby the gearbox, either.

Reliable, cheap, and proven fast. Not often that combo comes along. If you can, source a gearbox from a Mazdaspeed Miata, or at least from a 2001+ car - they have better shift feel than the earlier boxes do.

What rear end ratio are you using?

Currently, this guy is running a five speed wth a 3.63 rearend, giving him a top speed of 165mph and he flats out...

With the 6speed, he would lose topspeed...are there any options on a plug and play lower gear set? I've heard rumours about the 3.3 diff, some say it fits, some say it won't...

Remember, we're from Germany, so here's is actually the possibility to do that kind of speed...

The question is not whether the 3.308 fits - it's whether it exists at all. Some say it does, others have searched and say it does not. 6-speed and 3.63s with a 7400rpm rev limiter gives you 165mph worth of gear to play with.

I am using a 3.909 as is everyone else, with the exception of one 4.10 car. I tried the 3.63s and didn't like them - IMO you need at least 300whp to make them work, and probably closer to 325-350whp. For my goals, I'll stick with the 3.909s.

Andrew, who makes the 3.63 gear or is it available from another model? Exactly the gear ratio I am looking for...

Old manual 626s had them but finding one is like looking for hen's teeth. Mazdaspeed sells them for $400.

Thanks hustler... I will keep an eye out for one. Maybe if I can get ahold of one, I have have Richmond Gears make a duplicate in a more durable material for my setup as they are local. /thread jack

I believe richmond gear looked into this with a group buy in m.net a few years ago and not enough people ponied up the cash to make it worth-while for them to produce any.

Yeah, I found that thread on M.net. Might be able to talk them into it as I have buddies who do rock crawling and some of the employees there hang out with them. Worth a shot at least... If I can get it to happen I will post a thread to gauge the interest of maybe having more than 2 of them made.

This gear comes with all 6speed Miatas in Europe...

There are a lot of people here who are willing to sell or trade it, as a common swap here for autocross + twisties is the 6speed combined with a 4.1 or even a 4.3.

The 4.3 for the big housing isn't available at all here...

Hi,
i´m the guy with the 3rd Gear Overdrive Gearbox. :-)

You can find the 3.6 diffs in every 6speed mx5 in germany/europe, like the anni,sportive models. The most people here change from 3.6 to 4.1, so sometimes you can get a complete 3.6 rearend for about 300-400€ at ebay.

With the Combi 5Sp and 3.6 i can use all 5 gears completely. I drive at the nordschleife and the nürburgring gp-course with this setup and i think its quicker for me to shift between 3-4-5, than 3-4-5-6. But you are right, its not quick, if i stay with a broken 3rd gear at paddock.

Tryed someone only to cool the oil of the 5sp down, or installed oil-nozzels for the gears? I measured at my rearend housing 248°F and i think the gearbox is not cooler.

I switched to a 6 speed after going through no less than seven 5 speeds. And Ive broken 3rd gear, 2nd gear and the gear that runs the secondary shaft for everything but 4th in different transmissions.

I always ran a short shifter with an extended shift knob in my 5 speed and I really liked it. I rigged it up to work in the 6 speed but found it interesting that the for aft movement feels like the right amount of throw but the side to side movement is way too tight, the distance the knob moves between the 1 and 3 gate is just ¾” . My first attempt at driving an autocross in anger with the 6 speed 3.909 combo required a couple shifts into third because the gearing is too low to stay in second for most autocrosses. Twice I hit 1st while accelerating and trying to hit 3rd. never done that before. With the 5 speed hitting 5th instead of 3rd was the occasional issue but it wasn’t so violent of a mistake as this. I really dont like the stock shifter any more because it feel way too far from the steering wheel and burried low in the tunnel.

With this gearing I doubt I will ever need to use second on a track any more but the 3rd through 6th ratios probably will be better than what I had before with second through 5th on the 5 speed. Just got to make sure I hit the right gears. For autocross the gearing just sucks most everything will require lots of shifts between 2nd and 3rd gears. If I had the money I would get the Quafe.

Bob

I have one but havent put it in yet, i ended up getting everything on m.net for about 750. Ill keep you posted, even though I'm defiantly not Andrew. Mazda comp has them, and they were factory in the Aussie 6 speed and 79-82 626.

You won't find much info from me on the 3.63s, unfortunately - I am very happy with my 3.909s and I have no plans to switch any time soon. You can get them out of 626s, or if you want a fresh set Mazdacomp has them.

I have the quaife trans gears on the track bitch w/a 3.9 torsen. I had a '99 w/6speed and I absolutely HATED the feel of the shifter. First gear was completely useless, even on a street car and was just plain annoying to use. It does seem to be a more robust transmission though, so if $ is tight I would go with the 6spd unless you like to waste your time R&R'ing your transmission every other track event.

I ahve a 6 with 3.63. I like the ratios because there is not so much shifting (I'm a bitch), and the rpm drop is much more relaxed on the highway. If my car were a copy of SavingAIDS, I'd possibly put the 4.10 back in, but even that is doubtful.

You'll get accustomed to the shifter with a little time. I have a 5-speed daily and I prefer the feel of the 5-speed outright, but I'm very comfortable with the 6-speed shifter and have no complaints.

I would not buy anything from Quaife. I bought a diff from them for my VW and it broke almost immediately and they would not warranty it. I've also done enough work on a car with a Quaife in it that I would never buy it, even if it were the same price as a 6-speed.

with 400whp, and a car that sees more road use than track use, the 6speed and 3.636 is great. the ratios actually matches my local tracks quite good too. but im not using the 6th gear at all on the small local tracks.. if i take the mx5 to the "ring", 6th gear will also be used :)

In Australia our 6 speed MX-5s (including the MSM) all have 3.6 diff ratios and it makes them almost boring to drive!!

would not have 3.636 with a stock engine.. i had 4.1 with my 400whp engine, and that was just silly.. spent more time changing gears, than accelerating.. (almost)
3.636 works on very high power cars, or for those just wanting low cruising rpms.

Its pretty easy to look at the 6-speed/3.63 ratios and determine they're slightly shorter in 1-5 than a 5-speed/4.3....then you have the bigger 6th too.

So yes, 6/3.63 is our god except for Savington because he has AIDS.

Ive got a 6-speed 3.9 combo @ ~250whp, love it.

I have the Quaife internals sourced from FM. It should handle anything you throw at it (Hustler's comments notwithstanding) and it gives you similar gearing to the stock 5-speed. Have a look at FM's gearing calculator to see what you can pull down the straight-aways (Flyin' Miata : Technical info : Gearing calculator). With your R&P and this box, you're good for over 170 mph. Not cheap, but it does offer what you're looking for.

Men use 3.909s because they are worth time on track, and men also know that 1st gear is for driving the car on and off the trailer and 2nd gear is for driving around the pits. Think of 3-4-5-6 as the most wicked 1-2-3-4 box you've ever driven, plus a pair of granny lows, and champagne will fall from the skies.

Unless you are an undeniable badass with 375whp, in which case 3.63s might be warranted.

Thanks for the good response.

Before i try a 6sp, i give the 5sp a last chance with cooling and oil-nozzles at the 1,2,3 and 5th gear.

http://carphotos.cardomain.com/ride_...0266_large.jpg

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[QUOTE=Sandro;534890]Thanks for the good response.

Before i try a 6sp, i give the 5sp a last chance with cooling and oil-nozzles at the 1,2,3 and 5th gear.

QUOTE]

I don’t think the seven 5 speed transmissions I have broken were from the oil getting too hot or lack of oil, simply too much torque. With over 300 ft-lbs and good rubber you might make a single track day if you’re lucky with the 5 speed. 250 ft-lbs might go significantly longer but it is still limited.

I have the 6 speed with a 3.909. I absolutely hate it for autocross, constantly having to make shifts between second and third at really awkward moments even with a 7400 rpm rev limit. Autocross typically has fast and slow sections but really no straightaways. 1st gear is good for about 10 feet and will get you from the stage line to the timer start line which is nice but can’t go fast enough in second on the fast sections. Kieth Brown kicks my ass with a DP miata wich is about 500 lbs lighter and has 174!!! naturally aspirated RWHP out of a 1.6l spinning to 9000 rpm. 5 speed on 13” slicks he is however a better autocross driver than me and would probably kick my ass driving my car.

I think I will love it on the track once I get use to 3rd being the low gear I think 3rd through 6th will be better suited for most tracks. I actually think the new 3rd gear will get me off tight corners much faster than I was with the 5 speed when I go to real race tracks.

Bob

I suddenly miss my old 4.10 r&p. :hustler:

Swap you my 4.10 torsen for your 3.6 :)

Ding ding ding. 3rd becomes your new super-tall 2nd (~70mph), and suddenly the 6-speed box makes a whole lot of sense on track.

Yes, i killed the last two 5sp transmissions at the nürburgring gp-course from Saturday to Saturday. :bang:

Here you can hear my 3rd gear at 1:25 in the warm-up from the second stint on this track day.

YouTube - TurboSandro's Channel

I measured outside the rearend housing 248F with a temp-sticker and i think the transmission oil could be similar. If you add some offset to the bearings 300F oil-temp could be possible.

I wouldn't even dream of ever trying to use a 5speed with any power/track abuse..

I just look at 5 speeds and they self-destruct.

What is your Vmax with the 6spd and 4.1?

Check post #22 and follow the link. You can calculate for any Miata gearbox and R&P ratio.

How often are you gays changing your gear oil in terms of track hours?

I achieve a GPS measured speed of 145 down the front straight of my local track, Pacific Raceway. A 6 speed with a 4.10 will only go 147 at 7400 rpm. This is a recipe for disaster in my opinion. Lengthy sustained high load at or near peak rpm creates huge combustion temperature loads and will result in turbos falling off and melted pistons and stuff. I need taller gears than that. I already blew up a GTR powered 323 GTX that didn’t have enough legs for that long straightaway.

With the 5 speed and 3.909 it would do ~160 and a 6 speed with the 3.909 will do 154. in reality to make things last for more than a weekend and not risk an overheat in a 20 minute session I try and keep it below 7000 rpm as much as possible. At 7000 rpm the 6 speed with the 3.909 will do 145, it is the lowest rear end ratio I would consider with the 6 speed. It might even be better than a 3.636 in some situations.

A 6 speed with a mysterious unobtainable 3.308 seems like an interesting combo. It would make all the first 3 gears useful agian. It is nice to not have as big of jump from second to 3rd like the stock 5 speed.

The 5 speed Quafe sets also can be used to make some very effective combos in gearing. Plus the 5 speed trans is 10 lbs lighter than the 6 speed.

Bob

But then you have to deal with Quaife.

I'm sorry you had such a bad experience with them but all the racers around here that are winning are running quaife diffs. Atleast the E30 racers are anyway.

I know several people (real people, not e-friends), who have broken Quaife parts.

Have any of these people broken the Miata Quaife gearset? As far as I know, they've held up extremely well. I've certainly had no issues with mine.

I know of one trashed Quaife box but I'm not saying who due to professional arrangements.

+1

6 speed / 3.9 for boosted cars on the track

Our track rental 99 that makes about 140whp uses a 6 speed / 4.3 which is perfect for it.

I think the issue with the 5spd box is the lack of ribbing. If you ever look at the two its very obvious that the casing of the 6spd is designed for more power. I think the problem is more of a flex in the case straining the internal gearing than the actual gearing being weak.

If both box's were equal in strength I would pick the 5sp box any day. Its one of the best boxes ever built as far as shift feel and natural no think shifting. The 6spd as BB pointed out has very close gear notches and makes you think to shift. I've never missed 3-4 more in any box at the track. IF it had a 1-2 and R lock out for the track it would be tits.

Hey Sav; What size tire are you running on your car? Pretty much made my mind up about going with 6 speed.

Think You mentioned the 2001+ six-speeds had a better feeling shift, but is there any real difference between the boxes? Are they equally as strong? For some reason I recall reading the mazdaspeed boxes are cryo-treated gearsets or something of that nature?

He's running 225/45/15 NT01's on x9's if I'm not mistaken..

Umm, pardon the stupidity, but, is it possible to mate 1.6L to a 6-speed?

Yes. Only 2 bolts will match on the starter, but that's OK. You'll need to splice a couple wires together for the reverse and other switches.

225/45 NT-01s on 15x9 6ULs.

The MSM boxes are cryotreated and have the best shift feel of any 6-speed, 90% as good as a 5-speed. The red Kraftwerks car I drove at BW last year had an MSM 6-speed and if it weren't for the shift points and gearing, I would never have known it. The 2001 boxes are almost as good. The 99 box I have is noticeably worse than the 2002 box I drove in a friend's car, although I replaced the 5/R shift fork when I had it rebuilt last year and the only shift I used to miss (4-5) is butter smooth now. It's a different gearbox and you have to get used to it, but they are way way stronger. I put a bunch of days at 200whp and a few days at 270whp on my 6-speed and it looked perfect when we had it open.

My mystery 6-speed shifts 10x better than my sister's MSM box...significantly better. I have the funky 4-5 shift problem on occasion though.

I frequently drive 5-speed daily and the 6-speed track toy and I'm indifferent to shifter feel.

I've put 8 track events on a 6-speed with no problems. TDR's red 290whp car seems to blow up transmissions once per track event, I'd say no more than 3 days on a 5-speed at the absolute most. He finally gave up on the 5-speed after the micro-polished and cryo treated 5-speed died in the first session at Hallett.

6-speed is the way, there is no fighting it.

6- speed fo sho no ifs ands or butts about it. Unless your friend likes having no teeth.

Look, ma, no teef!

When my 6sp box was out of commission with a messed up 5/R shift fork last year, I had to borrow a tranny for RTA and didn't even consider one of the multiple spare 5-speeds in the backyard. Found a 6-speed to borrow from a friend and helped him install it later on for the favor.

Even Matt Andrews ran a 6-speed once or twice at 400+whp and didn't break the thing.

At 400whp, I would start looking at an RX tranny swap. Mike's MSM 6 speed started giving him problems at that power level on the street. After 470whp, it's completely trashed.

I'd rather spend my money on something like a Jericho at that point.

If you need a hook up on 'em, lemme know.

Tim -

Maybe you could hook us up by making the adapter parts needed to run the RX7 Turbo II tranny! Still plentiful and cheap at this point. Who else here thinks they'd be used more if there was a regular source for the parts needed to install them?

I have naughty dreams of a nebulous car with a high-rpm SBC and a Jericho box.

+1

I already Faro'ed the spare trans I have. I made a dirty .dxf direct from the faro data a while back. See post 25. I'm sure I posted it here too (I mention a post here at mt.net)
http://forum.miata.net/vb/showthread.php?t=312954

http://www.inoneear.com/outtheother/MazdaBPTrans.DXF

If someone has a RX7 transmission I can measure that too. Clutch, flywheel, etc the more parts I can measure the more accurate and easier it will be to make solid models of everything. I'm sure i can even machine some of the plates here.

I have one of the discontinued 8.200 deck height (302 height) aluminum ford SVO race blocks sitting in my office, and a go-ahead by the owner to use it in the miata. It's an old Jesel PRI display so it's already machined for our lifters, rockers, and belt drive. I'm sure there's some CFE heads lying around i could borrow indefinitely too. 9000rpm wouldn't be a problem. :drool:

I just got done designing a belt drive for the new RHS aluminum raised cam LS block. About 10 minutes ago Dan (Jesel) said "you know we could put this one in that miata of yours instead" That's going to be sick.

I got the coolest job in the world.

That would be sick. 9000rpm aluminum 302 Jesel valvetrian motor with a Jericho dog box = sexy time.